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Wide Fitting Specialists - Order online or visit our London store. Call 0208 819 7756 for help and advice.

Understanding ISO EN 20345 For Safety Boot

You arrive at a new job and are told to buy safety boots which meet a list of safety specifications from the Health and Safety Executive before you are allowed on-site. Sound familiar?

The world of safety specifications can be bewildering, but our in-depth guide on safety boot specifications will help ensure you get the right safety boots for your next job to keep you safe and working.

In the UK, safety boots are required to meet certain safety standards to ensure the protection of workers.

ISO Safety Standards

ISO EN 20345 Safety Boot Standards

The primary safety specification for safety boots is defined by ISO. ISO is an international non-government organisation responsible for defining safety standards across countries.

The main safety standard used by safety footwear manufacturers is EN ISO 20345.

You may also see it written as BS EN ISO 20345:2011. The date at the end refers to the year of the standard was issued or updated. Most employers list the 2011 version in their safety requirements, although some use the older, less stringent 20345:2004 version. The newest version is EN ISO 20345:2021.

There are other ISO safety ratings but we will come back to those towards the end of the article.

Understanding ISO 20345:2011

Within EN ISO 20345 there are several different ratings to indicate the level of protection a safety boot offers against different risks and hazards. Safety boot with these ratings have been laboratory tested to protect you against the hazards identified under that rating to the level specified.

You will see these listed after the ISO 20345 rating.

When purchasing a pair of Safety boots, make sure they have the right ratings to ensure you are protected against the particular risks at your workplace.

If you are unsure what you need then we recommend you speak to the person responsible for Health and Safety at your workplace and they should be able to advise you.

At Wide Shoes, we clearly list the ratings of each Safety boot to make it easier to get the right footwear.

EN ISO-20345 – S1 Rating

A safety boots with an ISO 20345:2011- S1 rating. An S1 rating indicates protection against a range of hazards; protection for the toes and foot against impacts and crushes, antistatic properties, and energy absorption in the heel.

However it is important to note that, S1 safety boots do not provide protection against water, penetration, or slip resistance unless specified by an additional coding.

Here is the protection an S1 Rating gives you:

  • Toe Protection

    S1 Rating Safety footwear must provide protection for the toes against impacts and crushes with a force of at least 200 joules. This is equivalent to dropping a 20kg weight from a height of 1 meter onto the toe area of the safety shoe.
  • Electrical Resistance

    S1 Rating Safety footwear must have antistatic properties, and be able to resistance to an electrical charge between 0.1 and 1000 megaohms.
  • Heel Energy Absorption

    Safety footwear with an S1 Rating must provide energy absorption in the heel area, to reduce the impact on the feet when walking or standing on hard surfaces. The standard requires a minimum energy absorption value of 20 joules. A nice bonus of this is that they are usually well cushioned and comfortable, even on long shifts.
  • Resistant to Fuel Oil

    An S1 Rating show that the soles of the boots are resistant to fuel oil.

S1-P Rating

You may also see the S1 rating written as S1-P.

The P indicates in addition to the protections listed above, the boot also has midsole protection against sharp objects such as nails and other protrusions. Footwear with a P rating have been tested to withstand penetration forces up to 1,100Nm.

However S1-P are primarily designed for indoor environments and are not ideal for outdoor environments as they are not water resistant.

They can be worn outdoors but won’t last as long if you are often working in wet weather. You can offset this to some extent by making sure that you polish and clean the leather uppers regularly with a high quality wax polish.

EN ISO-20345 – S2 Rating

For workplaces that require additional protection against water penetration and absorption, S2 safety boots are a good choice. They offer all the protection of S1 boots, as well as being water-resistant.

EN ISO-20345 – S3 Rating

For workplaces that require even greater protection, S3 safety boots are the recommended option. In addition to all the safety features of S2 footwear, you get added midsole protection against sharp objects.

Other EN ISO 20345 Ratings

Not all work boots have an S rating and you may also see other codes after ISO 20345:2011 to indicate what protection the boots offers against different hazards.

Here are the main codes you might see:

SB - Protective Toecap

The basic safety standard for footwear. Any product that is classified as SB has a protective toecap against a 200-joule impact.

It is important to note that the protection is just at the toecap, and do not offer protection against other risks such as underfoot penetration, electrical or slippery surfaces.

SB styles may have additional safety features which will be recognised via other codes. For example, SB-P means the safety footwear also has the additional feature of penetration resistance of the midsole to 1,100Nm.

HRO -Heat Resistant Outsole

Safety boots with the HRO code have heat resistance soles that have been tested to 300°C.

P- Midsole Protection

Safety boots with the P code have midsole protection against sharp objects, such as nails and other protrusions, and have been tested to withstand penetration forces of up to 1,100Nm.

A – Antistatic Protection

Safety boots with the A code offer electrical resistance between the foot and the ground ranging from 0.1 to 1000 Megaohms. 

E – Energy Absorption

Safety boots with the E code have energy absorption at the heel which has been tested at 20J. This is important for long shifts and this rating typically indicated a comfortable boot.  

SRA / SRB / SRC -Slip resistant against particular hazards

These ratings are used to indicate the level of slip resistance safety footwear offers.

Which rating is used depends on what substances they have been tested on.

SRA safety footwear has been tested on ceramic tiles with NaLS lubricant.
SRB safety footwear has been tested on steel with glycerol lubricant.
SRC safety footwear has been tested with both NaLS and glycerol lubricants.

FO - The outsole is resistant to Fuel Oil

OB - Footwear meets basic requirements which is to only have a non-slip sole.

WR - The safety boot is Water Resistant.

WRU - The shoe is designed with a Water Resistant Upper.

Other ISO Safety boot ratings

While the EN ISO 20345 is the most commonly used standard, you may see other EN ISO ratings listed when searching for Safety footwear.

EN ISO 20346

This specification sets out the requirements for safety footwear that provides protection against intermediate risks. These risks may include impacts and crushing, but at a lower level than those specified in EN ISO 20345.

EN ISO 20347

This specification sets out the requirements for occupational footwear that is designed for use in low-risk working environments. This may include workplaces where there are no significant risks of impact, crushing or penetration.

EN 50321-1

This specification applies to electrical insulating footwear that is designed to protect against electric shock. This type of footwear must provide insulation against electrical currents and be able to withstand certain levels of voltage.

EN ISO 17249

This specification sets out the requirements for safety footwear that provides protection against chainsaw cuts. This type of footwear must have a chainsaw-resistant layer that can withstand certain levels of cutting force.

Final Thoughts on ISO Safety Standards

Overall, the BS EN ISO 20345:2011 and other ISO standards are an important benchmark for the safety and performance of occupational footwear, helping to ensure that workers are protected against the hazards they may face in their workplace. 

Use the filter guide on our Wide Fit Safety Boot page to ensure the safety boot or shoe you purchase have the required protection for you to work safely and comfortably.

If you are still unsure what work boot is best for your foot condition and workplace then we are are happy to offer you advice and guidance. Please give us a call or email and we would be happy to help.

If you are in the Wembley area then why not arrange an appointment to come and visit, or use our walk in service. You can view the complete range and ensure you get the perfect fit and protection against the hazards in your workplace.


Frequently Asked Questions

I need a boot with midsole protection against nails and other penetrating objects, what do I look for?

You need to look for a boot with an S3 rating, or an S1 rating with a P (S1P), which indicates that the S1 boot also has mid-sole protection. We have added a filter to our safety boot collection so you can quickly find the boots that offer mid sole protection.

Click here to view our range of extra wide fitting safety boots with a S1-P or S3 rating.

I suffer from very swollen feet, what width safety boots should I look at?

Look for a safety boots with a 6E width fitting.

We would recommend the Wide Load range of safety boots as they have an extra wide and deeper toe cap than standard work boots.

Our range of 6E width safety boots come in a range of safety standards including ISO20345 S1 and S3. We also have boots in 6E fittings with mid sole protection (S1-P)

Click here to view our range of safety boots in an extra wide 6E fitting.

I need a work in a high security setting and need a safety boot which doesn’t set off metal detectors. What ones do I look at?

You need to choose a safety boot with a composite safety toe. They still offer the same level of protection as a steel toe cap but are made from non-metallic materials.

We have added a filter to our safety boot collection so you can quickly find the boots which have composite safety toes.

Our range includes includes composite toe safety boots and composite toe safety shoes.

Click here to view our range of extra wide safety boots with a non-metallic safety toe.

I work outside and want a boot with a waterproof upper and sole. Which boots offer that?

You should look for the WR or WRU coding in the ISO safety standard description. The WR indicates that the boot is water resistant. The WRU coding indicates that the boots also has a water resistant upper.

Use our quick filter on the safety boot page to quickly find the safety boots that offer this feature or click the link below.

Click here to view our range of wide fit safety boots with water resistant uppers.

I have custom orthotics from my doctor, how do I find boots that are suitable for them?

Lots of our safety boots have removable insoles so you can remove them and replace with your own orthotics. Use the quick filter on the safety boot page to find compatible boots or click the link below.

Click here to view our range of work boots with removable insoles.

What is the difference between ISO 20345:2004, ISO:20345:2007 and ISO 20345:2011?

The date indicates when the standard was updated or amended. A revision usually includes additional and/or more stringent requirements

The date suffix on the ISO rating for a safety boot indicates which edition and set of standard the boot meets and is usually dependent on when the boot was initially manufactured.

So a boot initially designed in 2006 would have an ISO 20345:2004 rating, while one initially designed in 2018 would need to meet the minimum standards of the ISO 20345:2011 certification, which would be the live version of the standard at the time of manufacture.

This does not mean boots with older ISO 20345 certifications are not safe or suitable for the workplace. Unless your workplace advises you of a specific ISO 20345 version then a safety boot with a 2004 version date should give you the protection you need to be safe at work. If you have any doubts then we would recommend speaking to the person responsible for health and safety at your workplace.

Should I choose a safety boot or safety shoe?

This depends on whether you need ankle protection and support. Some workplaces require a safety boot for this reason.

If you do not need ankle protection the a safety boot or safety trainer can offer all the protection required and many prefer the look and lighter weight of this type of safety footwear.




ISO – International Organisations For Standards -

Health And Safety Executive -